Is Syria's balance of firepower close to a tipping point?

As Free Syrian Army blames ammunition shortage for pulling back in Damascus, regime is also struggling with logistics issues

Free Syrian Army members preparing to move into Salahedinne in Aleppo on 9 August. Examination of photos and video suggests mosts opposition weapons are of Syrian origin. Photograph: Zohra Bensemra/Reuters

There is a modern military saying: amateurs talk tactics, professionals talk logistics. If evidence were needed of the truth of that, it was supplied last month in the fighting in Syria's capital, Damascus, when an offensive by opposition forces sputtered out as its fighters ran short of ammunition.

In the fighting for Aleppo the same problems seem to be recurring. On Thursday opposition fighters, under heavy pressure from a regime assault, finally pulled back from the Salahedin neighbourhood. As they did they blamed shortages of ammunition, not least of rocket-propelled grenades (RPGs), which some commanders have said they have been using at a rate of some 60 a day. Petrol, too, has increasingly become an issue.

But is not only the opposition that has had problems with logistics. According to reliable accounts, the Syrian armed forces have also had difficulties, not least in maintaining the serviceability of the attack helicopters on which they have become increasingly reliant.

In a conflict in which President Bashar al-Assad's armed forces appear unable to defeat an opposition growing ever more effective, both tactics and logistics have suddenly become crucial. So what has happened?

The reality is that while the military balance between the two sides remains hugely uneven, the opposition has been able to play to its advantages – in the short term at least – while the regime has found it increasingly difficult to exploit its strengths as the fighting has moved to the country's largest cities.

When the conflict began, the Assad regime had more than 300,000 troops under arms and could call on more than 100,000 militia and paramilitary personnel. While defections and combat casualties are likely to have made some inroads into that total, experts believe regime forces are still likely to be two to three times larger than the 70,000 or so the Free Syrian Army claims to have fighting on its side.

The regime also maintains its monopoly on air power, with little hard evidence that the FSA – despite its claims to the contrary – has significant numbers of anti-aircraft missiles or the training to use them.

In terms of armour, opposition forces remain hopelessly outgunned, claiming just over half a dozen captured tanks and some other armoured vehicles against the almost 5,000 the regime had at the outbreak of hostilities.

Despite all that, analysts believe things have changed. "My sense is that the military balance is shifting," said Jeffrey White, a former US intelligence officer who now comments on Syria for the Washington Institute for Near East Policy.

"People are always looking for the mythical turning point in Syria. There has not been a decisive moment but there has been a change."

White, like others, believes that one decisive factor has been improvements by the FSA's fighters in using what weapons are easily available to them, captured or bought from the army, and improvements in the quality of their leadership despite continued heavy losses among leaders.

"What they have got – like small arms and RPGs – they are using much more effectively," he said. "They are also using captured anti-aircraft systems like the ZU-23s and Dushkas much better."

The result, White believes, is that the regime is taking ever higher numbers of casualties. "In the last couple of months we are talking about 150-160 killed a day," he said.

What is counterintuitive – despite all the talk of weapons deliveries for the FSA paid for by Gulf allies such as Saudi Arabia and Qatar and talk of US and Turkish intelligence and co-ordination assistance – is how little hard evidence there is so far of large amounts of weapons being delivered from outside. What evidence there is of weapons entering the country suggests that so far it has largely been small arms. JBelgian journalist and blogger Damien Spleeters has been attempting to identify the source of small arms that do not appear to come from the Syrian military, including Belgian-made FAL and Austrian Steyr AUG rifles that have been seen in rebel hands.

Some reports have suggested they have been smuggled from Libya via Iraq into northern Syria. Instead, examination of still photographs, videos and first-hand reports indicates that most of the weapons acquired by the opposition are of Syrian origin, largely older, Soviet-supplied equipment.

One fighter interviewed by Reuters in late July described how his own unit, operating in Idlib province, had obtained its heavy weapons. "We took their anti-aircraft guns, the booty, and left a dozen of their men dead," said Radwan al-Saaour, 26, a former labourer from Latakia.

"We did not have the experience to lay explosives, or any coherent leadership … but this is now changing," said Khaldoun al-Omar, another rebel interviewed at the same time. "The battles are looking more like warfare between two armies, even though they far outgun us."

The growing effectiveness of the FSA has been fuelled by a number of factors that are likely to be increasingly important even if the rebels lose the current battle for Aleppo.

As the Assad regime has lost control of more of the rural areas, the opposition has found it easier to move men and arms, while denying the same ability to the regime.

Despite that, some observers believe the regime retains considerable military resilience in terms of personnel and equipment. They argue that Assad's generals, anticipating a crisis over the Golan Heights, had topped up their military arsenal to be able to fight a two-year conventional conflict against Israel if necessary.

However, a number of experts say that one significant feature of the latest phase of the fighting appears to be a change in tactics by the regime.

While some have interpreted this as a shortage of artillery in place around the city, other have suggested that it signifies an increasing unwillingness to risk the loss of troops loyal to Assad through casualties or defection.

Colonel Richard Kemp, a former British army commander who contributed to a recent report by the thinktank RUSI on the trajectory of the Syrian conflict, said he had heard "whispers" of the FSA acquiring anti-aircraft missiles from outside, "but nothing concrete". But he believes that most of the assistance from the US and its Gulf allies is likely to have been with communications, training and intelligence. He also pointed out that the regime has been in receipt of similar aid from Iran and Russia.

"The question in any case is how useful sophisticated weapons would be to a force like the FSA," he said, adding that Turkey and the US are likely to be cautious about supplying anti-aircraft weapons that could fall into the wrong hands.

"People will remember what happened in Afghanistan where it was necessary to have a buy-back programme for Stingers that were supplied."

Like others, Kemp has detected a change of regime tactics in the battle for Aleppo as the FSA has grown more confident militarily. "It is possible that is because the regime itself is aware that the more the fighting escalates, the greater the risk there is of outside intervention," he said.